A Study of 1-3 Pseudo-Random Pillar Piezocomposites for Ultrasound Transducers

The goal of our research is to develop a new diced 1-3 piezocomposite geometry to reduce pulse-echo ring down and acoustic cross-talk between high frequency ultrasonic array elements. Two PZT-5H based 1-3 composites (10 and 15 MHz) with different pillar geometries (square (SQ), 45 degrees triangle (TR), and pseudo-random (PR)) were fabricated and then made into single element ultrasound transducers. The measured pulse-echo waveforms and their envelopes indicate that the PR composites had the shortest -20 dB pulse length and strongest sensitivity among all the composites. Using these composites, 15 MHz array sub-apertures with a 0.95 lambda pitch were fabricated to measure the acoustic cross-talk between array elements. The combined electrical and acoustical crosstalk between the nearest array elements of the PR array sub-apertures (-32 dB @ 15 MHz) was 6 dB and 2 dB lower than that of the SQ and the TR array sub-apertures, respectively. These results demonstrate that the 1-3 piezocomposite with the pseudo-random pillars may be a good choice for fabricating enhanced high frequency linear array ultrasound transducers; especially when mechanical dicing is used.